Blow forming apparatus for producing double-walled vessels

• US 3,932,104 A
• Filed: 04/29/1974
• Issued: 01/13/1976
• Est. Priority Date: 04/29/1974
• Status: Expired due to Term

• Current Assignee: Robert F. Schneider
• Original Assignee: Robert F. Schneider
• Inventors: Schneider, Robert F.
• Primary Examiner(s): Husar, Francis S.
• Assistant Examiner(s): Safran, David S.
• Application Number:
  US05/464,811
• Time in Patent Office: 624 Days
• Field of Search: 425/DIG. 209, 425/DIG. 234, 425/DIG. 206, 425/387 B, 425/503
• US Class Current: 425/503
• CPC Class Codes: B29C 2049/023 using inherent heat of the preform, i.e. 1 step blow moulding
• CPC Class Codes: B29C 49/0031 Making articles having hollow walls
• CPC Class Codes: B29C 49/04 Extrusion blow-moulding
• CPC Class Codes: B29C 49/06 Injection blow-moulding

Abstract

Apparatus is disclosed herein for blow forming a double-walled container or body using either injection or extrusion molding techniques. A mold is provided having a movable sleeve which separates and defines a pair of coaxial wall cavities in parallel relation for receiving a parison during injection molding. A mold is further provided for movably positioning its halves about a pair of coaxial cylindrical parisons so as to close the opposite ends of a predetermined length, this latter procedure being an extrusion molding technique.

Claims

1. An apparatus for blow forming of hollow bodies so as to produce a double-walled vessel, the combination comprising:

a mold including a pair of mated halves having an open cavity defined by the shape of opposing internal wall surfaces;

sleeve means disposed over said open cavity for separating supplied parison within said mold cavity into coaxial inner and outer tubes;

means forming a portion of said mold at its extreme opposite ends for joining the opposite ends of said coaxial inner and outer tubes to seal said circular space between said inner and outer tubes so as to constitute the double walls of said vessel;

an extrusion die for extruding the parison into said cavity;

said sleeve comprising a part of said die whereby parison is divided into a pair of downwardly depending coaxial tubes into said mold cavity;

said joining means comprises cut-off portions at opposite ends of said mold cavity for severing said parisons and engaging the terminating ends of said tubes together in an integral joint;

means for trapping air between the opposing surfaces of said inner and outer tubes comprising;

air means for introducing pressurized air into the center of said coaxial tubular parisons urging the parisons into the form of said cavity.